Carrierwave cache storage

[jonatasrancan]

Since carrierwave 2.0.0rc if you don't specify which cache store to use, it will try to use the cache store implemented on the used storage. Before this the default options was to use file storage as default strategy for the cache.

carrierwave-colore doesn't implement the cache! method so we ended up getting some exceptions.

Need to implement #cache! if you want to use CarrierWave::Storage::Colore as a cache storage.

When this was introduced
https://github.com/carrierwaveuploader/carrierwave/blob/master/CHANGELOG.md#changed

And the commit
carrierwaveuploader/carrierwave@629afec#diff-a2fae088fb0c57593e3c4c6bd69bc382L189

Should carrierwave-colore handle cache as well or just fallback to file storage, like it was befere?